A theoretical individual-based model of Brown Ring Disease in Manila clams, Venerupis philippinarum

The susceptibility of Irish-grown and Galician-grown Manila clams, Ruditapes philippinarum, to Vibrio tapetis and Brown Ring Disease

Resistance to Brown Ring Disease in the Manila clam, Ruditapes philippinarum: A study of selected stocks showing a recovery process by shell repair

A proteomic study of resistance to Brown Ring disease in the Manila clam, Ruditapes philippinarum

Impact of Brown Ring Disease on the energy budget of the Manila clam Ruditapes philippinarum

The present work investigated the health status of the Manila clam in Ireland, with particular reference to brown ring disease (BRD) caused by V. tapetis which has been responsible for high mortalities of this bivalve throughout Europe. BRD was diagnosed in Ireland in the 1990s, causing heavy mortalities in Manila clam stocks in the north-west coast. In the current study, samples of clams from an Irish hatchery were obtained and screened from two sites, Drumcliff Bay, Co. Sligo and Dungloe Bay, Co. Donegal. Turbellarians and trematodes with some minor infections were the only parasites observed. Clams were examined for BRD, by analysis of shell valves for brown ring signs, and for V. tapetis by microbiological methods and by polymerase chain reaction (PCR). BRD was not diagnosed in cultivated clams from either site. It was, however, diagnosed in residual clams, which had survived the initial outbreak of BRD in the 1990s in Dungloe Bay. V. tapetis, however was detected in clams from both sites. Additionally, BRD was diagnosed, and V. tapetis isolated, in a once-off sample of clams from Mulroy Bay, Co. Donegal, where clams had been on-grown from imported seed. Minor heterogeneity at the 16S rDNA gene was observed between some sequenced products from Mulroy Bay and from Drumcliff Bay and Dungloe Bay indicating that in addition to V. tapetis, a V. tapetis-like strain may have been present in Mulroy Bay. The detection of V. tapetis in asymptomatic clams in Drumcliff Bay and Dungloe Bay may indicate that disease development may only occur when a number of factors combine to induce disease symptoms.

Since 1987, the Manila clam Ruditapes philippinarum has been regularly affected by the brown ring disease (BRD), an epizootic caused by the bacterium Vibrio tapetis. This disease is characterized by the development of a brown deposit on the inner face of valves. While most of the clams die from the BRD infection, some of them are able to recover by mineralizing a new repair shell layer, which covers the brown deposit by a process of encapsulation. The purpose of this work was to study the organic matrix of the shells of Manila clams in the inner shell layer before, during and after the brown deposit and during the shell repair process by confocal Raman micro-spectrometry and wavelength dispersive spectrometry (WDS) microprobe. In addition, the organic matrix of the repaired shell layer was extracted and quantified, by using standard biochemical shell matrix extractions protocols. The brown deposit exhibited high luminescence intensity in Raman spectra, and an increase of S, C, Sr (forming two peaks) and a decrease of Ca, Na concentrations (% w/w), using WDS microprobe mapping and cross-sectional transects. The signature of these trace elements was similar to that recorded on periostracal lamina (% w/w). The high S concentration likely corresponds to the presence of a high amount of sulfated organic compounds. Interestingly, on cross-sectional transects, before the brown deposit, a thin layer of the shell showed also a high luminescence, which may suggest that this layer is modified by bacteria. After the brown deposit, at the beginning of the shell repair process, the luminescence and the S concentration remain high, before declining the level found in non-BRD-affected shells. Quantification of the organic matrix shows that the shell repair layer zone is significantly different from non-BRD-affected shell layer, in particular with a much higher amount of insoluble matrix.

Report on the occurrence of brown ring disease (BRD) in Manila clam, Ruditapes philippinarum, on the west coast of Korea

Metabolic responses of clam Ruditapes philippinarum exposed to its pathogen Vibrio tapetis in relation to diet

The bacterium, Vibrio tapetis, is the aetiological agent of Brown Ring Disease (BRD), which affects the Manila clam, Venerupis (Ruditapes) philippinarum. Two PCR assays for detection of V. tapetis were applied to a sample of 52 Manila clams, and evaluated in comparison with the more traditional V. tapetis detection method of microbiological isolation and characterization, as well as the traditional BRD diagnostic technique of shell valve analysis. The pathogen was detected in 15.4% of the sample using the PCR assay of Rodriguez et al. (2003, 2006) in 50% of the sample using the PCR assay of Paillard et al. (2006) and in 36.5% of the sample by microbiological methods. Whereas shell valve analysis was the least sensitive technique, detecting BRD in 7.7% of the sample, it was an essential diagnostic tool because it was the only technique that identified the disease, rather than the aetiological agent. None of the four techniques was sufficient on its own for effective BRD diagnosis; rather various c...

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 430:35-48 (2011) - DOI: https://doi.org/10.3354/meps09111 Effects of toxic Alexandrium tamarense on behavior, hemocyte responses and development of brown ring disease in Manila clams V. M. Bricelj1,*, Susan E. Ford2, Christophe Lambert3, Annaick Barbou3, Christine Paillard3 1Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, New Jersey 08901, USA 2Haskin Shellfish Research Laboratory, Rutgers University, Port Norris, New Jersey 08349, USA 3Institut Universitaire Européen de la Mer, LEMAR, Technopôle Brest Iroise, 29280 Plouzané, France *Email: mbricelj@marine.rutgers.edu ABSTRACT: In this study of short-term exposure of Ruditapes philippinarum from Brittany, France, to an Alexandrium tamarense isolate that produces high concentrations of paralytic shellfish toxins (PSTs), the effects of the isolate on clam fitness, toxin uptake, and the response of hemocytes (responsible for internal defense in bivalves) were examined. Adults exhibited individual variability in ­resistance to the effects of PSTs, measured by their burrowing capacity. If genetically based, this may (1) indicate that resistance is under natural selection and (2) provide a new model to advance our understanding of the molecular basis for PST resistance in bivalves, so far determined only in Mya arenaria. Juvenile clams were more vulnerable to PSTs than adults, experiencing 100% burrowing incapacitation within 1 d of exposure to A. tamarense. They also experienced growth suppression and high mortalities following 4 d of toxification. Juveniles challenged with Vibrio tapetis, the cause of brown ring disease (BRD), and exposed to A. tamarense, developed significantly fewer BRD symptoms relative to controls fed non-toxic algae, but suffered higher mortality. Adult clams exposed to A. tamarense showed a significant increase in hemocyte concentrations and a small, but significant, decrease in phagocytic activity, and no effect on hemocyte viability or other functional parameters. We speculate that the inhibitory effects on BRD progression may be attributable to toxicity of PSTs to V. tapetis, inability of juveniles to activate the shell conchiolin-deposition response, and/or an overall increase in phagocytic cells induced by A. tamarense. Harmful algae and pathogens may thus ­interact and modulate the effects of disease in bivalve populations. KEY WORDS: Ruditapes philippinarum · Paralytic shellfish toxins · Vibrio · Burrowing · Hemocytes Full text in pdf format PreviousNextCite this article as: Bricelj VM, Ford SE, Lambert C, Barbou A, Paillard C (2011) Effects of toxic Alexandrium tamarense on behavior, hemocyte responses and development of brown ring disease in Manila clams. Mar Ecol Prog Ser 430:35-48. https://doi.org/10.3354/meps09111 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 430. Online publication date: May 26, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.

A quantitative estimation of the energetic cost of brown ring disease in the Manila clam using Dynamic Energy Budget theory

Transcriptomic analysis of Ruditapes philippinarum hemocytes reveals cytoskeleton disruption after in vitro Vibrio tapetis challenge

Haemocyte parameters associated with resistance to brown ring disease in Ruditapes spp. clams

A short-review of brown ring disease, a vibriosis affecting clams,<i>Ruditapes philippinarum</i>and<i>Ruditapes decussatus</i>

Effects of the pathogenic Vibrio tapetis on defence factors of susceptible and non-susceptible bivalve species: II. Cellular and biochemical changes following in vivo challenge